Suspension device

ABSTRACT

A heat engine unit has a combustion chamber, the combustion chamber being in communication with a previous component of the heat engine unit, e.g., a compressor, a heat exchanger or a recuperator, at a first end, and in communication with subsequent stages of the heat engine unit at a second end. The combustion chamber comprises at least one part, and is allowed to expand when exposed to heat by being movably engaged at the first end. The combustion chamber is supported at the second end by way of a contact surface formed between the second end of the combustion chamber and supporting means to allow tilting of the combustion chamber.

FIELD OF THE INVENTION

[0001] The present invention relates to a combustion chamber for a heat engine unit, the combustion chamber being in communication with a previous component of the heat engine unit, e g a compressor, a heat exchanger or a recuperator, at a first end, and in communication with subsequent stages of the heat engine unit at a second end.

PRIOR ART

[0002] A gas turbine can be of an axial or radial type with one or more compressor and/or turbine stages, depending on the power and heat requirement, and available space. Different power requirements and heat outputs lead to different sizes and types of gas turbines. One feature often common for the different types of gas turbines is that a combustion chamber is provided either inside the gas turbine or externally. The most common way of increasing the efficiency of the gas turbine is to raise the temperature of the combustion air before it enters the combustion chamber, this is often done by interchanging the excess heat in the exhaust gas. The temperature in the combustion chamber is often high, whereby demands on sealings and heat expansion durability is high. The sealing problem during uneven heat expansion and heat distribution may be solved in many ways, one way is to design the combustion chamber with overlapping ends, wherein each end is designed with for example bulges corresponding to grooves in the adjacent surrounding surface allowing some movement before the sealing vanishes.

[0003] This solution of a combustion chamber has a disadvantage, it does not allow any tilting of the combustion chamber, i e the overlapping parts has to keep an essentially parallel relation for ensuring a sufficient sealing. This allows only small movements for the combustion chamber for reducing gas leakage, when the combustion chamber is thermally strained, i e by heat expansion, during operation of the gas turbine unit.

SUMMARY OF THE INVENTION

[0004] The main objects of the present invention are to simplify the construction, assembly and maintenance of combustion chambers in heat engine units, reduce the number of working moments during the assembly, and enhance the sealing of the combustion chambers during thermal strain.

[0005] These objects are achieved for heat engine units by providing them with an combustion chamber according to the invention. The present invention relates to a combustion chamber for a heat engine unit, the combustion chamber being in communication with a previous component of the heat engine unit, e g a compressor, a heat exchanger or a recuperator, at a first end, and in communication with subsequent stages of the heat engine unit at a second end. The combustion chamber comprises at least one part, and the combustion chamber is allowed to expand when exposed to heat by being movably engaged at said first end. Furthermore, the combustion chamber is supported at said second end by way of a contact surface formed between said second end of the combustion chamber and supporting means to allow tilting of the combustion chamber.

[0006] By providing a heat engine unit with a combustion chamber according to the invention, a simpler construction reduces associated working moments during assembly. Moreover, the contact surface formed between the combustion chamber and the supporting means permits tilting of the combustion chamber. Also, the installation and maintenance of the combustion chamber are simplified due to an easier procedure when changing combustion chambers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention will now be described in further detail, reference being made to the accompanying drawings, in which:

[0008]FIG. 1 is a side view in section showing a preferred embodiment of a combustion chamber according to the invention mounted in a heat engine unit.

DETAILED DESCRIPTION OF THE INVENTION

[0009]FIG. 1 shows a combustion chamber 10 according to the invention mounted in a heat engine unit 20. In this embodiment the heat engine is in the form of a gas turbine and is described as a gas turbine in the following. The combustion chamber comprises at least one exhaust gas outlet 30, a housing 40, at least one air intake 50, a connecting member 60, and supporting means 70.

[0010] The combustion chamber 10 is shown assembled between the connecting member 60 of the gas turbine unit 20 and the supporting means 70 located before a subsequent gas turbine stage (not shown). The combustion chamber has two ends, a first end 10 a and a second end 10 b, wherein the housing 40 of the combustion chamber comprises two parts, a first part 80 and a second part 90. The centre of the first part 80 coincides with the centre of the second part 90, and the first part 80 and the second part 90 also form the second end 10 b of the combustion chamber. The inner diameter of the first part 80 is larger than the outer diameter of the second part 90 for containing a portion of the second part, preferably a main portion. The difference in diameter forms a space between the first and second part, which creates the at least one air intake 50. The air intake receives air, shown by an arrow C, from a compressor stage (not shown).

[0011] The combustion chamber has its first end 10 a in engagement with a suspension, arrangement 100 placed in the connecting flange 60, and its second end 10 b in engagement with and supported by the supporting means 70 in the form of a gas channel. The suspension arrangement comprises three symmetrically spaced springs, which are detachably attached to the first end 10 a of the combustion chamber, but may have any number of springs, the most important is that the force of the springs on the combustion chamber is evenly transferred. The connecting flange 60 is rotary symmetrical and holds support members 110, at least one gas inlet 120, and at least one ignition member 130, these parts point in the axial direction towards the combustion chamber 10 and are in engagement thereto. The support members 110 are attached to and holds a gas combustion part 140 in which, for example natural gas is delivered through the at least one gas inlet 120 and mixed with air delivered from the at least one air intake 50, whereby the gas mixture is ignited by the at least one ignition member 130 and then delivered through the at least one gas outlet 30 into the supporting means 70 for further delivery to the gas turbine stage. The first part 80 of the combustion chamber 10 and the second part 90 are attached together by a detachable arrangement 180 at the second part 10 b of the combustion chamber.

[0012] The combustion chamber 10 may be manufactured in many ways, for example by wrapping a plate into a cylindrical shape, whereby the joint along its length is welded tight, here, the combustion chamber is preferably made by casting.

[0013] The combustion chamber 10 preferably has a cylindrical cross-section but may have any other shape of the cross-section, which is obvious to a person skilled in the art. These different shapes depend on, e g available space in the gas turbine unit 20 or the design of the surrounding area delivering the combustion air and/or receiving the exhaust gas, for example the area receiving the exhaust gas may have a non-symmetrical shape, whereby the cross-section of the combustion chamber must have a cross-section that varies along its length in the radial direction, i e transversally in relation to its length, e g from a cylindrical shape at its first end 10 a into an oval shape at its second end 10 b. Moreover, the cross-section of the combustion chamber 10 could have a quadratic or rectangular shape or even a cross-section with 5 sides forming a pentagon-shaped cross-section at one end or both ends, if required according to the demands described above. In order to improve the cooling of the combustion chamber, i e enhance the turbulence around the outer shape, any of the two parts 80 or 90 could have a rough inner or outer surface in the radial direction, i e transversally in relation to its centre axis, for example ribs, bulges or grooves extending radially around the whole periphery or portions of it.

[0014] The supporting means 70 has a rotary symmetrical shape, preferably a cylindrical shape extending towards the combustion chamber 10 at one end and extending in the opposite direction towards the gas turbine stage at a second end. The combustion chamber may have a non-symmetrical shape if required, for example the two parts 80 and 90 of the housing 40 could have their centre axis displaced in relation to each other.

[0015] The combustion chamber 10 is supported by the supporting means 70 by way of a spherical outer surface 150 provided at its second end 10 b being in contact with a conical inner surface 160 of the supporting means during operation of the gas turbine unit 20. The contact surface or support surface formed between the spherical outer surface and the conical inner surface has the shape of a tangential circumferential contact surface 170, which allows tilting of the combustion chamber. FIG. 1 also shows an enlargement of the spherical outer surface 150 and the conical inner surface 160 for clarity reasons. The radius of the spherical outer surface is designated with an arrow R. The radius R is defined so that it fulfills the condition that the contact point between the spherical outer surface and the conical inner surface always is in a position on the conical inner surface which gives the largest moving area for the combustion chamber in both directions independently of how the combustion chamber tilts.

[0016] The radius R may be in the interval of about 50-150 mm but the size of the radius R depends on several factors, e g the dimensions of the associated parts, especially the diameter of the combustion chamber 10 and also the conical angle of the conical inner surface. In this case, the preferred radius R for the spherical outer surface 150 is about 75-85 mm and most preferred about 80-85 mm when the conical angle at the conical inner surface 160 is 45°. Other conical angles is conceived by a man skilled in the art , e g a conical angle of 30° in combination with other dimensions of the combustion chamber would give another radius, i e these parameters depend on each other.

[0017] The tilting function for the combustion chamber 10 is required as the combustion chamber 10 may, in some cases, have an askew position, due to an uneven thermal expansion and/or a non-uniform distribution of the surrounding pressure from adjacent parts expanding in different directions both radially and axially due to high temperatures, e g the supporting means 70 in the form of a gas conduit, which has to be compensated for by tilting the combustion chamber.

[0018] Still, a sufficient sealing has to be maintained between the gas inside the combustion chamber 10 and the surrounding both in the possible askew position for the combustion chamber and during thermal expansion for associated parts and the combustion chamber. This is achieved by way of the suspension system 100 provided at the first end 10 a of the combustion chamber 10. The suspension system 100 in the form of springs bias the combustion chamber in the axial direction towards the supporting means 70, whereby the second end 10 b of the combustion chamber, i e the spherical outer surface 150, is in contact with associated sealing surfaces, i e the conical inner surface 160, at all times even though it tilts. The suspension system also permits movement of the combustion chamber during expansion or shrinking due to cooling in the axial direction.

[0019] The first end 90 a of the second part 90 of the combustion chamber 10 extends over a portion of the gas combustion part 140, which has an outer guiding surface 170 in the direction towards the gas turbine stage. This guiding surface works as an axial expansion space when the combustion-chamber 10 expands axially due to thermal strain, i e heat expansion, when the gas turbine unit is operated. The main thermal axial expansion for the second part 90 of the combustion chamber 10 occurs in the direction towards the connecting flange 60, i e in the expansion space of the guiding surface 170, the second part 90 always overlapping the maximum distance that may be covered by the first end 90 a of the second part 90 when shrinking due to cooling, whereby any build-up of strain or forces in the axial or radial direction is eliminated.

[0020] The contact surface 170 created between the spherical outer surface 150 at the second end of the combustion chamber 10 and the conical inner surface 160 of the supporting means ensures that a sufficient sealing always is maintained independently of how much the exhaust diffusor 10 tilts. A sufficient sealing may also be achieved by placing the spherical surface on the supporting means 70 and the conical surface in the combustion chamber or designing both surfaces with a spherical shape. The conical inner surface 160 could also be placed on the outside of the supporting means 70 and the spherical surface 150 on the inside of the second end 10 b of the combustion chamber.

[0021] The spherical or conical surfaces may also be placed on an outer portion of the combustion chamber 10 between the first end 90 a of the second part 90 of the combustion chamber and the second end 10 b of the combustion chamber.

[0022] The combustion chamber 10 is made of a heat resistant metal but can of course be made of any other material fulfilling the thermal demands, e g ceramics. 

1. A combustion chamber (10) for a heat engine unit (21), the combustion chamber being in communication with a previous component of the heat engine unit, e g a compressor, a heat exchanger or a recuperator, at a first end (10 a), and in communication with subsequent stages of the heat engine unit at a second end (10 b), characterized in that the combustion chamber (10) comprises at least one part, in that the combustion chamber (10) is allowed to expand when exposed to heat by being movably engaged at said first end (10 a), and in that the combustion chamber is supported at said second end (10 b) by way of a contact surface (170) formed between said second end (10 b) of the combustion chamber and supporting means (70) to allow tilting of the combustion chamber.
 2. A combustion chamber (10) according to claim 1, wherein the at least one part of the combustion chamber comprises at least two parts, a first part (80) and a second part (90), which are attached together, wherein a first end (80 a) of said first part and a first end (90 a) of said second part constitute said first end (10 a) of the combustion chamber.
 3. A combustion chamber (10) according to claim 1, wherein a suspension arrangement (100) is attached to the first end (10 a) of the combustion chamber for biasing the combustion chamber in the axial direction against said supporting means (70).
 4. A combustion chamber (10) according to claim 2, wherein the combustion chamber is lodged to slide at said first end (90 a) of said second part (90) of said combustion chamber.
 5. A combustion chamber (10) according to claim 3, wherein the combustion chamber is allowed to expand in the axial direction due to said first end (80 a) of said first part (80) in the combustion chamber being attached to said suspension arrangement (100) in the form of at least one spring allowing movement of the combustion chamber.
 6. A combustion chamber (10) according to any of the claims 1-5, wherein said contact surface (170) is formed by way of a spherical surface (150) at the second end (10 b) of the combustion chamber being in contact with a conical surface (160) of said supporting means (70), or by way of a conical surface at the second end (10 b) of the combustion chamber being in contact with a spherical surface of said supporting means (70).
 7. A combustion chamber (10) according to any of the claims 1-5, wherein said contact surface (170) is formed by way of a spherical surface (150) located on an outer portion of said second part (90) of the combustion chamber between the first end (90 a) of said second part and the second end (10 b) of the combustion chamber, and is in contact with a conical surface (160) of said supporting means (70), or by way of a conical surface located on an outer portion of said second part (90) of the combustion chamber between the first end (90 a) of said second part and the second end (10 b) of the combustion chamber, and is in contact with a spherical surface of said supporting means.
 8. A combustion chamber (10) according to any of the claims 1-5, wherein said contact surface (170) is formed by way of a spherical surface (150) at the second end (10 b) of the combustion chamber being in contact with a spherical surface of said supporting means (70).
 9. A combustion chamber (10) according to any of the claims 2-8, wherein said first part (80) of said combustion chamber has a larger inner dimension in relation to the outer dimension of the second part (90) of said combustion chamber for containing the main portion of said second part.
 10. A combustion chamber (10) according to any of the claims 2-9, wherein the centre of said first part (80) of said combustion chamber coincides with the centre of the second part (90) of said combustion chamber.
 11. A combustion chamber (10) according to claim 3 or 5, wherein the suspension arrangement (100) comprises three springs.
 12. A combustion chamber (10) according to any of the claims 6-8, wherein said spherical surface (80) has a preferred radius of about 50-150 mm and most preferred about 75-85 mm.
 13. A combustion chamber (10) according to any of the previous claims, wherein said combustion chamber is made of a heat resistant material, e g metal or ceramics.
 14. A combustion chamber (10) according to any of the previous claims, wherein said combustion chamber is rotation symmetrical.
 15. A combustion chamber (10) according to any of the previous claims, wherein said combustion chamber has a cross-section with at least three sides. 